Physics
Case 1: Lata cuts a potato into two halves, using a cutter which belongs to a Class II lever. She needed effort E1.
Case 2: Then she cuts one half of this potato again, but this time she needed effort E2. If E1 > E2 then:
(a) In which case (1st or 2nd) was the potato closer to her hand applying the effort? (Assume normal reaction of the surface of the potato is same in both cases)
(b) Give a reason for your answer in (a) above.
Answer
(a) The potato was closer to her hand in Case 1.
(b) The cutter acts as a Class II lever, in which the load lies between the fulcrum and the effort. When the potato is placed closer to the hand applying effort, it is farther from the fulcrum, so the load arm becomes longer. For a fixed effort arm, a longer load arm requires greater effort to cut. Since E1 > E2, the potato must have been closer to her hand in the Case 1.
Related Questions
Complete the following by choosing the correct answers from the bracket:
(a) A car is moving in uniform circular motion. The direction of friction between the tyres and the path is …………… [towards the centre / tangential to the path].
(b) When a ray of light passes from a denser to a rarer medium, its wavelength …………… [decreases / increases].
(c) The lid of a calorimeter minimises heat loss by …………… [convection / radiation].
(d) Quality of sound depends on its …………… [amplitude / waveform].
(e) A substance whose resistance becomes almost negligible at a temperature near absolute zero is called a …………… [semiconductor / superconductor].
(f) …………… radiation deviates minimum in a magnetic field [Alpha / Beta].
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The graph below shows the variation of image distance (v) with the object distance (u) when an object is kept in front of a lens.
(a) Identify the type of lens used.
(b) What would be the magnification (more than 1 / less than 1 / equal to 1) if the object is placed between F and 2F of the above lens?
A resistance R is connected across a cell with a switch and a rheostat in series. A voltmeter is connected parallel across the cell. Current in the circuit is increased using the rheostat.
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(b) Justify your answer stated in (a) above.